This is a major release with several important changes, coming almost three years after the latest major release (1.11).

The most significant new feature in this release is certainly the support for the TAP testing protocol in the Automake-generated testsuite harnesses.

There is also at least one long-awaited bug fix: now, any explicit enabling or disabling of a warning category always take precedence over the set of warning categories implied by the strictness mode. For example, a setting like "AUTOMAKE_OPTIONS = -Wall --foreign" will cause the warnings in category 'portability' to be enabled, even if those warnings are by default disabled in 'foreign' strictness. This wasn't the case for older Automake versions.